This invention relates to nuclear reactors and it has particular relationship to the replacement of old split-pin assemblies (OSPA's), mounted in the flange of the lower guide tube (LGT), by new split-pin assemblies (NSPA's). Howell discloses apparatus for accomplishing his purpose. This apparatus includes a saw-and-drill stand and an installation stand. These stands are suspended submerged in about 20 feet of water from the walls of the pool of a nuclear reactor plant. The saw-and-drill stand serves to remove the OSPA's. The saw of the stand severs each old split-pin usually above the crotch where the tines join producing a split-pin fragment and another fragment. Then the other fragment is drilled usually upwardly and is broken into a fragment including the flange of the pin and another fragment including the nut and the fragment of the pin to which the nut is threaded. The three fragments are readily removed from the guide tubes and disposed of.
The Howell apparatus has performed highly satisfactorily. But it is desirable to further simplify the process of removing the OSPA's and it is an object of this invention to accomplish this purpose.